122 research outputs found
Femto- és attoszekundumos fény-szilárdtest kölcsönhatások vizsgálata kontrollált hullámformájú lézerimpulzusokkal = Investigation of femto- and attosecond light-solid interactions with controlled-waveform laser pulses
A projekttámogatásnak köszönhetĹ‘en 2006-2009 között felĂ©pĂtettem egy komplex mĂłdon használhatĂł femtoszekundumos lĂ©zerlaboratĂłriumot, amelynek fĹ‘ fĂ©nyforrása egy Ăşn. hosszĂş rezonátoros Ti:zafĂr lĂ©zeroszcillátor, amely a hasonlĂł oszcillátorokhoz kĂ©pest kĂ©t nagyságrenddel nagyobb impulzusenergiát szolgáltat. Ennek segĂtsĂ©gĂ©vel kĂĽlönbözĹ‘ femtoszekundumos optikai technolĂłgiai kĂsĂ©rleteket vĂ©geztem, mint pĂ©ldául erĹ‘sen diszperzĂv tĂĽkrök elsĹ‘kĂ©nt törtĂ©nĹ‘ tesztelĂ©se rezonátoron belĂĽl, fehĂ©r lĂ©zerfĂ©ny előállĂtása az impulzusok összenyomásának cĂ©ljábĂłl stb. ElmĂ©leti Ă©s kĂsĂ©rleti kutatást folytattam továbbá kĂĽlönbözĹ‘ nagy intenzitásĂş, ultragyors fĂ©ny-anyag kölcsönhatási folyamatok vizsgálatára, kĂĽlönös tekintettel az Ăşn. felĂĽleti plazmonos elektrongyorsĂtásra. | Based on the project support between 2006-2009, I built a complex femtosecond laser laboratory with a so-called long-cavity Ti:sapphire oscillator as the main light source. This delivers two orders of magnitude more pulse energy than similar standard oscillators. With this laser, I carried out various femtosecond optical technological experiments such as the intracavity testing of highly dispersive mirrors for the first time, the generation of white laser light for pulse compression etc. In addition, I carried out tehoretical and experimental research for the investigation of high-intensity, ultrafast light-matter interaction phenomena with a particular focus on the so-called surface plasmon enhanced electron acceleration
Lézer-indukált ultragyors fémfelületi folyamatok vizsgálata. = Study of laser-induced ultrafast processes on metal surfaces.
A kutatási tervvel összhangban, a Max Planck Kvantumoptikai IntĂ©zettel valĂł egyĂĽttműködĂ©snek köszönhetĹ‘en felĂ©pĂtettĂĽnk Budapesten egy egyedi, 200 nJ-os, 40 fs-os impulzusokat adĂł Ti:zafĂr oszcillátort. A fĂ©ny-anyag kölcsönhatások ultragyors dinamikájával kapcsolatos elmĂ©leti Ă©s kĂsĂ©rleti kĂsĂ©rleteket vĂ©geztĂĽnk mind Budapesten mind NĂ©metországban, kĂĽlönös tekintettel a felĂĽleti plazmonok által erĹ‘sĂtett elektrongyorsĂtás vizsgálatára. Ezeket az eredmĂ©nyeket rĂ©szben már publikáltuk, a 2008-ban törtĂ©nt mĂ©rĂ©sek eredmĂ©nyeinek publikálása pedig folyamatban van. | According to the research plan, based on the collaboration with the Max Planck Institute for Quantum Optics we built a unique Ti:sapphire oscillator delivering 200-nJ, 40-fs laser pulses. We also carried out studies related to the ultrafast dynamics of light-matter interactions both in Budapest and in Germany with particular focus on the investigation of the so-called surface plasmon enhanced electron acceleration. These results were partly published during the project and the publication of the 2008 measurement results is under way
Geographic information systems in the pay of alternative tourism – methods with landscape evaluation and target group preference weighting
There is a large variety of types of rural areas and many of them are rich in landscape beauty. However, their preserved culture and traditions are revalued in today’s rapid transformation of lifestyles. Alternative tourism is thus an emerging potential to economically support these areas, at the same time helps to preserve natural and cultural heritage. The methods provide sophisticated means to analyse the characteristics and the potential attractiveness of landscape and cultural attractions from the viewpoint of alternative tourism development. Homogenous tourism sub-regions can be defined and the most suitable development scenarios can be found to the certain areas
Interpretation of sustainability in the utilization of renewable energy sources
The utilization of renewable energy sources (res) is crucial regarding to sustainable reconstruction of energy systems. The target is a balanced, sustainable development of Hungarian energy management considering equally the ecological, social and economic aspects. There are many different technologies of utilization of res varied by sources, conversion processes, size and products. The comparison of each technology and their sustainability assessment are required by the importance of efficient remodeling of energy infrastructure. The group of attributes was composed by numerous important parameters in the course of our analysis with the choice experiment (ce) methodology. The estimation of each attributes’ influence on the individual’s preferences and choices was possible by this method and the preferences of the statistical population was concluded. So thus the utility derived from each attribute was estimated. The result of the ce analysis for the population of experts is demonstrated in the current phase of our research
Az anyag attoszekundumos dinamikája ultraintenzĂv lĂ©zerterekben optikai cikluson belĂĽlii idĹ‘beli Ă©s hullámhosszon belĂĽli, nanomĂ©teres tĂ©rbeli tartományokban = Attosecond dynamics of matter in ultra-high laser fields with sub-cycle temporal and sub-wavelength, nanometer-scale spatial resolution
BebizonyĂtottuk, hogy az elektronok intenzĂv kvantált sugárzási tĂ©rrel valĂł kölcsönhatása fotonszám-fázis minimális bizonytalanságĂş, kĂĽlönleges statisztikájĂş fotonállapotok kialakulását eredmĂ©nyezi. ElemeztĂĽk a foton-elektron összefonĂłdást, a Hanbury Brown Ă©s Twiss (HBT) tĂpusĂş korreláciĂłk extrĂ©m (attoszekundumos) fĂ©nyjelek diagnosztikájában valĂł alkalmazhatĂłságát, Ă©s általunk bevezetett „attoszekundumos sörĂ©tzaj” szerepĂ©t. A felĂĽleteken (pl. vĂ©kony fĂ©mrĂ©tegen, plazmarĂ©tegen Ă©s grafĂ©nen) lejátszĂłdĂł intenzĂv lĂ©zer-anyag kölcsönhatásoknál elemeztĂĽk az Ăşn. vivĹ‘-burkolĂł fázis szerepĂ©t kĂĽlönbözĹ‘ nemlineáris folyamatokban. KifejlesztettĂĽk az elektronok kĂ©tdimenziĂłs kinematikájának Wigner-fĂĽggvĂ©nyes leĂrását. Az ultrarövid fĂ©nyimpulzusok grafĂ©nen törtĂ©nĹ‘ szĂłrĂłdásának elemzĂ©se során általunk elĹ‘rejelzett „relativisztikus levágás” optikai nĂ©gyszögimpulzusok generálását teheti lehetĹ‘vĂ©. KĂsĂ©rletileg Ă©szleltĂĽk Ă©s elmĂ©letileg Ă©rtelmeztĂĽk felĂĽleti plazmonok tĂ©rerĹ‘sĂtĂ©sĂ©t, s az evaneszcens terek nemlineáris optikai hatásait (felharmonikus-keltĂ©s, sokfotonos elektron emissziĂł Ă©s gyorsĂtás), Ă©s demonstráltuk, hogy az elektronok 2-3 femtoszekundumos csomagokban hagyják el a fĂ©mfelĂĽletet, az intenzitás-bulkolĂłt követve. A plasmon-bomláskor (kollektĂv fĂ©kezĂ©si sugárzásakor) keletkezĹ‘ ultrarövid fĂ©nyjelek nemklasszikus HBT-korreláciĂłját, Ă©s a fotoncsomĂłsodásbĂłl a ritkulásba valĂł átmenetet elsĹ‘kĂ©nt mutattuk ki Ă©s Ă©rtelmeztĂĽk az általunk kidolgozott elmĂ©let alapján. | We analysed entanglement in the interaction of electrons with a strong quantized radiation field, which leads to the generation of number-phase minimum uncertainty states. On the basis of these results we introduced the concept of ""attosecond shot-noise"" and shown how the Hanbury Brown and Twiss (HBT) type correlations can be used for probing extreme light signals. We developed the Wigner function description of the kinematics of electrons in two-dimensional geometry. We studied in details the role of carrier-envelope phase difference effects in strong field laser- matter interactions at surfaces (thin metal or plasma layers and graphene). We predicted the new phenomena of ""relativistic clipping"" appearing in the scattering of ultrasort pulses on graphene, which may lead to rectangular optical pulses. We have observed experimentally and described theoretically that in surface plasmon enhanced evanescent electric fields, strong-field optics effects exist (high-harmonic generation, nonlinear electron emission and acceleration). These are characteristic for surface plasmon physics, they otherwise occur only in fields, higher than those produced by our exciting laser. We demonstrated that the electrons leave the surface in 2-3 fs-long bunches, following the intensity envelope of the surface plasmons. We measured and theoretically interpreted for the first time HBT type correlations in decaying surface plasmon light, and found the transition from antibunching to bunching
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